Study of N-benzylidene derivatives synthesized as corrosion inhibitors for copper in HCl solution

Abstract

Corrosion inhibition of the two N-benzylidene derivative compounds, namely N-benzylidene pyridin – 2 amine (NBPA) and N-(4-choloromethylbenzylidene) pyridin – 2 amine (NCMBPA) as corrosion inhibitors for copper in hydrochloric acid 6.0 M have been studied by electrochemical methods such as potentiodynamic polarization measurements and electrochemical impedance spectroscopy. Potentiodynamic polarization results show that corrosion potentials shift to anodic regions in the presence of N-benzylidene compounds compared to the blank solution. The electrochemical measurements indicated that the inhibition efficiency for NCMBPA about 92% and NBPA about 85%. The adsorption of inhibitors on the copper surface follows from Langmuir adsorption isotherm. Activation energy (E_a), Gibbs free energy (ΔG_ads), enthalpy (ΔH*), and entropy (ΔS*) of corrosion process are determined by using the experimental measurements.